A flat panel display with thin body, power saving, no radiation and many other advantages, has been widely used. A conventional flat panel display device includes a liquid crystal display device (Liquid Crystal Display, LCD) and a organic electroluminescence display device (Organic Light Emitting Display, OLED). A thin film transistor (Thin Film Transistor, TFT) array substrate is an important part of a flat panel display device, may be formed on a glass substrate or a plastic substrate.
In the process of manufacturing the array substrate by number (Mask) process is used to reduce the reticle, can significantly reduce the manufacturing cost of the array substrate, and thus can reduce the manufacturing cost of the TFT-LCD. In the prior art, the process from the initial 7 photo-mask technology for manufacturing the array substrate 4 photo-mask current technology, are used to form a patterning gate, the patterned active layer and the source/drain electrodes, via holes of pixel Electrode, patterned pixel electrodes.
In addition, as the display panel resolution and size increase, the signal delay phenomenon will be more serious, and reduction of the wiring resistance has become an urgent need. Copper (Cu) is second only to silver (Ag) and has a low cost of raw materials. It is considered as the most promising low-resistivity wiring material. Copper has been used in the prior art as a wiring material on an array substrate. However, using copper as a wiring material on an array substrate has a problem of increasing the number of mask processes or increasing the difficulty of a mask process. Therefore, the way how to optimize the array substrate structure makes copper be used as a wiring material under a relatively simple process condition. This is a problem that the industry has been trying to solve.